Paving block



1967 P. SCHRAUDENBACH 3,301,148

PAVING BLOCK Filed D80. 18, 1963 IN VIVTOR p a4 SCHRHQOEN zinc/l United States Patent 6 3,301,148 PAVING BLOCK Paul Schraudenbach, Agnes-Bernauerstrasse 53A, Munich, Germany Filed Dec. 18, 1963, Ser. No. 331,417 Claims priority, application Germany, Dec. 19, 1962,

Sch 32,494 3 Claims. (Cl. 94-13) The present invention relates to a paving block, preferably of concrete, which consists of several parallel bar-shaped tread members of a trapezoidal cross section which are provided with transverse grooves at least in the upper side thereof, and of parallel connecting webs which extend transverse to the tread members. Each of these connecting webs has a length greater than the distance between the outer surfaces of the outer tread member. In accordance with the trapezoidal shape of the tread members, the cross-sectional size of the openings between the adjacent tread members gradually increases from the lower side to the upper side of the block. Paving blocks of this type have been previously developed by me and are well-known. They are being used for supporting parking vehicles, and have the advantage that, if grass is sown in the ground which fills out the openings between the tread members and webs, an area which is covered with such paving blocks has the appearance of a lawn.

As long as the areas which are covered with these paving blocks are equally loaded or are subjected to relatively small loads, for example, of passenger cars, the paving blocks will not change in position relative to each other.

Paving blocks of the aforementioned type may for average loads be very safely secured to the ground since the cross-sectional sides of the openings between the adjacent tread members gradually increases from the lower to the upper side of the block. The paving block will be securely anchored to the ground once the grass sod has been formed in these openings. Furthermore, since the area of the lower side of each paving block is larger than that of the upper side, any pressure exerted in a downward direction will be distributed over a larger bearing surface.

However, if relatively heavy loads of strong impact forces act upon these paving blocks, one or more blocks will tilt relative to the other from the horizontal plane of the paved area. Therefore, an end portion of the tilted block will project above the adjacent blocks. This is undesirable from the standpoint of both appearance and safety.

The underlying cause of the blocks of known construction shifting relative to one another is two-fold. First, the outer surfaces of the tread members which lie adjacent to each other have been constructed so as to extend in perpendicular planes. Second, no means has been provided for equally spacing adjacent blocks from one another a suflicient distance so as to form an additional opening within which sod may be formed.

It is an object of the present invention to improve the paving blocks of the above-mentioned type of such a manner that the individual blocks of an area which is paved with such blocks will not change in their position relative to each other when subjected to relatively heavy loads, such as of heavy trucks, or to strong impact forces such as may be produced, for example, by the landing of aircraft.

For attaining this object, the present invention provides that each tread member of the paving block is made of a length greater than the distance between the lateral outer surfaces of the outer transverse connecting 3,391,148 Patented Jan. 31, I967 ice webs. It is further provided that all of the tread members project with their full cross-sectional size beyond the outer transverse connecting webs, and vice versa. By making the paving blocks of such construction, each block of the paved area as well as the connection between adjacent blocks will be extremely stable once grass has been sown on the ground which fil-ls out the openings of each block and between adjacent blocks. The sod once grown in these openings will anchor the paving blocks so securely in the ground that their individual positions and their position relative to each other will remain unchanged even when subjected to very heavy loads or strong impact forces. The sod also forms a substantial root complex which additionally aids in preventing the blocks from shifting relative to one another.

The paving blocks according to the invention are preferably designed so that each end of each transverse connecting web extends beyond the respective outer tread member for a distance which is equal to one half of the distance between two adjacent tread members of each block. The sod layer which will then be formed between the outer tread members of adjacent paving blocks will then have the same width, length and anchoring power as the sod layer between the adjacent tread members of each block.

In combination with the above-mentioned feature, it is a further feature of the invention, although known as such, to support the individual paving blocks also directly on each other and to lock them to each other by providing the outer ends of the tread members with inclined surfaces and by inclining these surfaces alternately in opposite directions. It is then advisable to chamfer at least the acute edge between the upper side and the inclined end surfaces. If a paving block according to the invention is subjected to a load at a point where the tread members project beyond a connecting web, these tread members will rest on the tread members of the adjacent block and the load will thus be distributed over and taken up by two or more blocks. The supporting and locking effect may be further improved by divid ing each end surface of each tread member into three surfaces, the upper and lower of which extend vertically to the upper and lower sides of the tread member, while the central surface extends at an inclined angle.

These and further features and advantages of the present invention will become more clearly apparent from following detailed description thereof which is to be read with reference to the accompanying drawings, in which FIGURE 1 shows a perspective view of a paving block according to the invention;

FIGURE 2 shows a cross section which is taken through the end portions of the bar-shaped tread members of two adjacent paving blocks according to FIG- URE 1, in which the end surface of each of these tread members is composed of three different surfaces;

FIGURE 3 shows a cross section similar to FIGURE 2, but in which the end surface of each tread member forms one inclined surface; while FIGURE 4 shows a similar cross section of a modification of the paving blocks according to FIGURE 3.

Referring first particularly to FIGURE 1 of the drawings, the paving block according to the invention forms an integral unit which consists of a plurality of barshaped tread members 1 of an upwardly tapering cross section which extend parallel to each other and are separated by ohannellike openings 2 which extend entirely through the paving block from the upper to the lower side thereof and gradually decrease in width in the downward direction in accordance with the tapered shape of the tread members 1. Each of these openings therefore has a trapezoidal cross section in which the longer of the two parallel sides is located within the plane of the upper side of the paving block. The upper surfaces of the tread members 1 are interrupted by transverse grooves 3, the greatest depth of which is preferably less than the thickness of the tread member. These grooves 3 serve primarily for increasing the grip of the block especially on the tires of automobiles. Since these grooves do not communicate directly with the lower side of the block but only through the channellike openings between the tread members, there are no difficulties in cleaning these rids and, since they extend transverse to the channellike openings, it is also practically impossible when cleaning them to tear out the grass sod which is growing in these openings. Of course, the lower surfaces of the tread members 1 may also be provided with grooves similar to the grooves 3. All of the tread members 1 are connected to each other by transverse webs 4, the upper surfaces of which are preferably in alignment with the surfaces of the grooves 3, although this is not a necessary requirement. The particular paving block as illustrated in FIG- URE 1 is provided with four grooves 3 and two connecting webs 4. Each web 4 projects slightly beyond the lateral outer surfaces of .the outer tread members, namely, by a distance which is equal to one half of the space between two adjacent tread members. Consequently, when two paving blocks are placed adjacent to each other, three further openings will be formed between them. The number of tread members and grooves in each paving block is optional, and the grooves may also be provided at other points than shown in FIGURE 1. It is, however, an important feature of the invention that not only the connecting webs project over the lateral outer surfaces of the outer tread members, but also that the tread members project Over the lateral outer surfaces of the outer webs, and that both the tread members and web project with their entire cross-sectional area.

In order to insure that adjacent paving blocks according to the invention will also support each other, the end surfaces 6 of the tread members 1 are alternately inclined in opposite directions.

Whereas each end of each tread member 1 of the paving block according to FIGURES 1 and 2 is composed of three different surfaces 5, 6, and 7 or 5, 6, and 7 extending at an angle to each other, the ends 8 or 8 of each tread member of the paving block according to the modification as shown in FIGURE 3 form a single uninterrupted inclined surface. However, it is advisable to chamfer the acute edges between the surfaces at least at the upper side of each tread member so that each inclined surface 8' terminates into a chamfered surface 8" or 8', as shown in FIGURE 4. Of course, it is also possible to chamber the acute edges between the inclined surfaces and the lower surface of each tread member so as to form a chambered surface 8 Contrary to the appearance of the paving block in FIGURE 1, it is also generally advisable to avoid any sharp edges between the surfaces of the tread members and webs and to round ofi these edges so as to increase the resistance of such a paving block to breakage.

Paving blocks of the kind as above described have been subjected to rigorous tests which have shown that these blocks when connected to each other to form a larger unit will not change in position relative to each other even when subjected to very strong impacts.

The paving blocks according to the invention may be laid either parallel next to each other or in an offset relation to each other. If they are laid in such a manner that the blocks abutting against each other at their lateral longitudinal sides form a row, and if the adjacent rows are then offset relative to each other by the distance of approximately one half of the width of one block, each block Which is acted upon by an impact force will transmit this force not merely to the ground below but through its end surfaces to four other paving blocks, especially if this force is excessively strong.

Although my invention has been illustrated and described with reference to the preferred embodiments thereof, I wish to have it understood that it is in no way limited to the details of such embodiments, but is capable of numerous modifications Within the scope of the appended claims.

Having thus fully disclosed my invention, what I claim 1. A paving block comprising a plurality of bar-shaped parallel tread members spaced from each other and having at least one transverse groove in the upper side thereof, a plurality of parallel connecting webs extending transverse to said tread member, said connecting webs being spaced from one another so as to form an opening therebetween, said spaced tread members being of a cross-sectional size gradually decreasing from the lower side to the upper side of the block, each of said tread members having a length greater than the distance between the lateral outer surfaces of the outer webs, each of said we'bs having a length greater than the distance between the lateral outer surfaces of the outer tread members, all of said tread members projecting with their full cross-sectional size beyond the outer webs and all of said webs projecting with their full cross-sectional size beyond the outer tread members, and the end surfaces of adjacent tread members being alternately inclined in op posite directions.

2. A paving block as defined in claim 1, in which at least the acute edges formed between the upper side and the inclined end surfaces of said tread members are charnfered.

3. A paving block as defined in claim 1, in which the central parts of the end surf-aces of the adjacent tread members are alternately inclined in opposite directions and the upper and lower parts of said end surfaces extend substantially vertical to the upper and lower sides of said tread members.

References Cited by the Examiner UNITED STATES PATENTS 12,172 1/1855 Warner 9413 3,040,637 6/ 1962 Brernshey 94-11 FOREIGN PATENTS 162,712 4/ 1949 Austria. 1,135,701 8/1962 Germany.

141,95 1 4/ 1920 Great Britain.

JACOB L. NACKENOFF, Primary Examiner. 

1. A PAVING BLOCK COMPRISING A PLURALITY OF BAR-SHAPED PARALLEL TREAD MEMBERS SPACED FROM EACH OTHER AND HAVING AT LEAST ONE TRANSVERSE GROOVE IN THE UPPER SIDE THEREOF, A PLURALITY OF PARALLEL CONNECTING WEBS EXTENDING TRANSVERSE TO SAID TREAD MEMBER, SAID CONNECTING WEBS BEING SPACED FROM ONE ANOTHER SO AS TO FORM AN OPENING THEREBETWEEN, SAID SPACED TREAD MEMBERS BEING OF A CROSS-SECTIONAL SIZE GRADUALLY DECREASING FROM THE LOWER SIDE TO THE UPPER SIDE OF THE BLOCK, EACH OF SAID TREAD MEMBERS HAVING A LENGTH GREATER THAN THE DISTANCE BETWEEN THE LATERAL OUTER SURFACES OF THE OUTER WEBS, EACH OF SAID WEBS HAVING A LENGTH GREATER THAN THE DISTANCE BETWEEN THE LATERAL OUTER SURFACES OF THE OUTER TREAD MEMBERS, ALL OF SAID TREAD MEMBERS PROJECTING WITH THEIR FULL CROSS-SECTIONAL SIZE BEYOND THE OUTER WEBS AND ALL OF SAID WEBS PROJECTING WITH THEIR FULL CROSS-SECTIONAL SIZE BEYOND THE OUTER TREAD MEMBERS, AND THE END SURFACES OF ADJACENT TREAD MEMBERS BEING ALTERNATELY INCLINED IN OPPOSITE DIRECTIONS. 